Newcastle Disease Virus (NDV) is a member of the Avulavirus genus in the Paramyxoviridae family, which has been shown to infect a number of avian species (Alexander, D J (1988). Newcastle disease, Newcastle disease virus—an avian paramyxovirus. Kluwer Academic Publishers: Dordrecht, The Netherlands. pp 1-22). NDV possesses a single-stranded RNA genome in negative sense and does not undergo recombination with the host genome or with other viruses (Alexander, D J (1988). Newcastle disease, Newcastle disease virus—an avian paramyxovirus. Kluwer Academic Publishers: Dordrecht, The Netherlands. pp 1-22). The genomic RNA contains genes in the order of 3′-NP-P-M-F-HN-L-5′, described in further detail below. Two additional proteins, V and W, are produced by NDV from the P gene by alternative mRNAs that are generated by RNA editing. The genomic RNA also contains a leader sequence at the 3′ end.
The structural elements of the virion include the virus envelope which is a lipid bilayer derived from the cell plasma membrane. The glycoprotein, hemagglutinin-neuraminidase (HN) protrudes from the envelope allowing the virus to contain both hemagglutinin (e.g., receptor binding/fusogenic) and neuraminidase activities. The fusion glycoprotein (F), which also interacts with the viral membrane, is first produced as an inactive precursor, then cleaved post-translationally to produce two disulfide linked polypeptides. The active F protein is involved in penetration of NDV into host cells by facilitating fusion of the viral envelope with the host cell plasma membrane. The matrix protein (M), is involved with viral assembly, and interacts with both the viral membrane as well as the nucleocapsid proteins.
The main protein subunit of the nucleocapsid is the nucleocapsid protein (NP) which confers helical symmetry on the capsid. In association with the nucleocapsid are the P and L proteins. The phosphoprotein (P), which is subject to phosphorylation, is thought to play a regulatory role in transcription, and may also be involved in methylation, phosphorylation and polyadenylation. The L gene, which encodes an RNA-dependent RNA polymerase, is required for viral RNA synthesis together with the P protein. The L protein, which takes up nearly half of the coding capacity of the viral genome is the largest of the viral proteins, and plays an important role in both transcription and replication. The V protein has been shown to inhibit interferon-alpha and to contribute to the virulence of NDV (Huang et al. (2003). Newcastle disease virus V protein is associated with viral pathogenesis and functions as an Alpha Interferon Antagonist. Journal of Virology 77: 8676-8685).
Naturally-occurring NDV has been reported to be an effective oncolytic agent in a variety of animal tumor models (Sinkovics, J G, and Horvath, J C (2000). Newcastle disease virus (NDV): brief history of its oncolytic strains. J Clin Virol 16: 1-15). Naturally-occurring strains of NDV have been used in multiple clinical trials against advanced human cancers (Sinkovics, J G, and Horvath, J C (2000). Newcastle disease virus (NDV): brief history of its oncolytic strains. J Clin Virol 16: 1-15; Lorence et al. (2007). Phase 1 clinical experience using intravenous administration of PV701, an oncolytic Newcastle disease virus. Curr Cancer Drug Targets 7: 157-167; Hotte et al. (2007). An optimized clinical regimen for the oncolytic virus PV701. Clin Cancer Res 13: 977-985; Freeman et al. (2006). Phase I/II trial of intravenous NDV-HUJ oncolytic virus in recurrent glioblastoma multiforme. Mol Ther 13: 221-228; Pecora et al. (2002). Phase I trial of intravenous administration of PV701, an oncolytic virus, in patients with advanced solid cancers. J Clin Oncol 20: 2251-2266; Csatary et al. (2004). MTH-68/H oncolytic viral treatment in human high-grade gliomas. J Neurooncol 67: 83-93). However, the success of naturally-occurring strains of NDV in these clinical trials for advanced human cancers was only marginal (Hotte et al. (2007). An optimized clinical regimen for the oncolytic virus PV701. Clin Cancer Res 13: 977-985; Freeman et al. (2006). Phase I/II trial of intravenous NDV-HUJ oncolytic virus in recurrent glioblastoma multiforme. Mol Ther 13: 221-228; Pecora et al. (2002). Phase I trial of intravenous administration of PV701, an oncolytic virus, in patients with advanced solid cancers. J Clin Oncol 20: 2251-2266). As such, there remains a need for NDV-based therapies useful in the treatment of cancer, especially advanced cancer.